Safety device for a winch



J. R. SMITH June 2, 1970 SAFETY DEVICE FOR A WINCH Filed July 5. 1968 lNVENTOR JAMES R. SMITH BY. (vlad/l United States Patent O 3,515,247 SAFETY DEVICE FUR A WINCH James R. Smith, Martinsville, Ind., assignor to Baker- Roos, Inc., Indianapolis, Ind., a corporation of Indiana Filed July 5, 1968, Ser. No. 742,707

Int. Cl. F16d 63/00 U.S. Cl. 18S-82.1 4 Claims ABSTRACT OF THE DISCLOSURE A safety device for preventing rotation of a winch drum when said rotation becomes excessively fast in one direction. One end of the drum is provided with radially extending slots in which a plurality of slides are carried. The slides are held axially within the slots by a support plate having a stop and a guide mounted thereon. The slides, which move radially outwardly` to within the radial extent of the stop when the drum is rotated too fast in one direction, engage said stop and prevent further rotation of the drum. When thedrum is rotated in said one direction at a normal rate of speedsaid slides, under the iniluence of gravity, clear the stop, and when the drum is rotated in an 4opposite direction, the guide causes the slides to clear said stop. v

Background ofthe disclosure e Winches are generally provided with regulating means for controlling their rotational drum speeds. Such ,regulating means may fail, however, permitting the Wmch to lunwind too rapidly, thereby causing great damageto the Summary of the i invention I In accordance withthe invention, I provide a safety "mi" device for a winch which is operative to prevent rotation of a winch drum when the rotationalspeed of sald drum becomes excessive. A plurality of slides supported against axial movement are carried in a plurality of radial slots m at one end of a winch drum. The slides areI forced outwardly from the drum axisV under the'effect of centrifugal force when the drum is rotated at excessive speeds in one direction to contact a stop block which is xedly mounted adjacent said one end of the drum and thus prevent further rotation of the drum in said one direction. This safety action is normally only necessary when the winch cable is being unwound, since the load upon which the winch operates will tend to prevent excessively rapid rotation of the drum when the cable is being taken up thereby.

The stop block is mounted on a support in a position at one end of the drum horizontally offset from a vertical plane through the drum axis. Said block is placed slightly above the horizontal axis of the drum, and a guide is lixedly mounted on said support below the block. In one direction of drum rotation the guide directs the slides past the block, while in the other direction of rotation the guide does not effectively interfere with the movement of the slides so that the latter may contact the stop block to prevent further rotation of the drum when the rate of said rotation becomes excessive.

Under normal drum speeds, the slides move to the outer limits of their respective slots under the force of gravity when their slots are directed downwardly during drum rotation. As the drum rotates, thereby causing slots to extend upwardly, gravity causes the slides to slide back toward the drum axis. Upon failure of the normal speed controls, however, faster rotation of the drum vcauses the centrifugal force on the slides to overcome the force of gravity on said slides, and they are thus prevented from sliding back toward the drum axis. Therefore, they strike the 'stop block and prevent further rotation of the drum.

Brief description of the drawings v The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a side elevation of a winch assembly havmg a safety device embodying my invention;

FIG. 2a is an enlarged vertical section taken along line 2 2 of FIG. l, and showing the winch drum in a slowly rotating or rest position;

FIG. 2b is an enlarged vertical section also taken along line 2 2 of FIG. 1, but showing the winch drum in a rest position after having been stopped by the safety device; and

FIG. 3 is a sectional view taken along line 3 3 of FIG. 2a.

`Detaileddescription of the preferred embodiment In the embodiment shown, one end of the shaft 14 is ydriven by means of a pair of meshed gears 22 and 24 attached respectively to the shaft 14 and to the rotating shaft of a drive motor 26 mounted on the base plate 20. Controls (not shown) are provided for controlling the speed of rotation of the motor.

A safety device embodying the invention is provided `at theend plate 40. As shown in FIG. 2a said device compr1ses four slides 30 slidably retained in slots 32 in the plate 40. The slots 32 extend radially outwardly in the outer face of the plate 40 to an annular outwardly projecting flange 42 formed on said plate. The standard 18 is positioned adjacent the end plate 40 to thus hold the slides 30 against axial movement between the end plate and the standard.

A stop 34 in the form of a bar is ixed to the inner face of the standard 18. The distance between the inner face of the stop 34 and the end. plate is less than the distance that the outer faces of the slides 30 project outwardly from the plate 40 so that when any one of the slides is disposed within the radial extent of the stop 34 it will engage said stop and prevent drum rotation. As shown in FIG. 2a, the stop 34 is mounted on the standard 18 slightly above the horizontal plane through the axis of the drum, and on the side of a vertical plane through said axis through which the drum rotates downwardly when the cable is being paid out by the drum. A guide 36 for the slides 30 is mounted on the inner face of the standard 18 and is formed by an arcuate bar positioned along a radius corresponding to the distance from the center of the shaft 14 to the innermost edge of the stop 32. As shown, one end of the guide abuts the stop 34 while its opposite end extends tangentially from the curved portion of the guide to a point at least intersecting with the flange 42. Thus, in one direction of rotation, as the winch is taking up the cable (clockwise as viewed in FIG. 2a), the slides contact the guide at the tangential portion thereof, and said guide causes the slides to move radially inwardly in their slots to prevent them from engaging the stop 34. Conversely, as the winch rotates slowly in an opposite direction (counterclockwise as viewed in FIG. 2a), the slides are disposed as shown in that figure. That is, each slide slides downwardly as shown at 30a when the slot in which the slide is carried extends downwardly from the drum axis. As the drum rotates, each slide slides back toward the drum axis, as shown at 30b, when the slot in which it is carried extends upwardly from the drum axis. Thus, when the drum is rotated slowly, each slide 30 passes the stop 34 irrespective of the direction of drum rotation. However, when the speed of the drum reaches a certain r.p.m. level as the drum is being rotated in a counterclockwise direction as viewed in FIGS. 2a and 2b (normally the direction in which the cable 12 is being paid out), the slides are again slid downwardly by gravity and centrifugal force when their slots extend downwardly lfrom the drum axis. However, the centrifugal force prevents the slides from sliding back toward the drum axis when their slots extend upwardly therefrom. This causes said slides to be disposed within the radial extent of the stop 34 so that the next slide attempting to pass said stop abuts it as shown at 30a` in FIG. 2b. Such interference stops the rotation of the winch drum in that direction until the conventional speed control mechanism is repaired.

While the slides 30 have been illustrated as blocks in the drawings, it is to be understood, of course, that said slides may be of any desired configuration, and to this end, they may be in the form of balls movable in the slots 32.

I claim:

1. In combination with a winch having a drum adapted to be rotated about a horizontal axis and provided with a pair of end plates, a safety device comprising a plura'lity of radially extending slots formed in the outer face of one of said end plates, a standard parallel to said one end plate and closely spaced thereto, a slide slidably carried in each of said slots and projecting axially therefrom, means for limiting the inward yand outward radia'l movements of said slides, said standard axially positioning said slides in said slots, a stop mounted on the face of said standard adjacent said one end plate Within the radial extent of said slots, said stop being in a position above a horizontal plane through the drums axis and to one side of a vertical plane through said axis to engage said slides when said slides are moved radially outwardly into the path of said stop when the drum is rotated in one direction to prevent further rotation of said drum in said one direction, and 'guide means on said face of said standard adjacent said one end plate and extending arcuately outwardly from a position on said stop nearest the drum axis for guiding said slides past said stop when the drum is rotated in an opposite direction, the end of said guide means opposite said stop being radially spaced from the drum axis a distance equal to at least the distance that the slides are free to slide outwardly from the drum axis.

2. In combination with a winch having a drum adapted to be rotated about a horizontal axis and provided with a pair of end plates, a safety device comprising at least one radially extending slot formed in the outer face of one of said end plates, a slide slidably carried in said slot and projecting axially therefrom, means for preventing axial movement of said slide with respect to said end plate, a stop disposed within the radial extent and outside the axia'l extent of said slot, said stop being in a position above a horizontal plane through the drums axis and to one side of a vertical plane through said axis to engage said slide when said slide is moved radially outwardly into the path of said stop when the drum is rotated in one direction to prevent further rotation of said drum in said one direction, and guide means extending arcuately downwardly from a position on said stop nearest the drum axis for guiding said slide past said stop when the drum is rotated in an opposite direction, the end of said guide means opposite said stop being radially spaced from the drum axis a distance equal to at least the distance that the slide is free to slide outwardly from the drum axis.

3. The invention as set forth in claim 2 in which said means for preventing axial movement of said slide comprises a standard for said winch having an inner face parallel with said one end plate, and said stop and `guide means are mounted on said inner face of said standard.

4. The invention as set forth in claim 2 in which means are provided for limiting the sliding movements of said slide in said slot outside the extent of said guide means.

References Cited UNITED STATES PATENTS 227,146 5/1880 Campbell 18S-82.1 X 2,791,397 5/1957 Coifman 254-157 X 3,149,702 9/1964 Popper 188-185 GEORGE E. A. HALVOSA, Primary Examiner U.S. C1. X.R. 

